Scientists in the US have grown hair on “nude” mice, bred to be bald from birth, using grafts of master cells that form new hair follicles and sprout fresh fur.

The findings raise the prospect of the most effective therapy yet for those who are unhappy at losing their hair.

If skin stem cells are found to be as versatile in people as they are in mice, it should be possible to use them to “seed” the scalp with new follicles that restore a lustrous head of hair.

The study also opens the way to using stem cells to regenerate skin for treating burns victims and people who are disfigured by scars.

A team led by Elaine Fuchs of Rockefeller University in New York investigated the characteristics of stem cells found in a section of mouse hair follicles known as the “bulge”.

Previous experiments had indicated that these should be capable of forming new follicle and skin tissue but it had not been possible to coax them to develop this way in the laboratory.

Dr Fuchs and her colleagues isolated these stem cells from the bulge and grew them in culture to produce a full range of skin tissue — skin cells, follicle cells and sebaceous gland cells that secrete an oily substance that lubricates the skin.

The researchers then grafted colonies of these stem cells on to the skin of “nude” mice to determine whether they could start hair growth in a living animal that had no working follicles of its own.

Fresh skin cells of every type appeared at the site of these grafts — including healthy hair follicles that sprouted thick tufts of fur. In some cases the new fur was almost as dense as naturally occurring fur.

The findings, details of which are published today in the journal Cell, suggest that stem-cell grafts could one day restore hair growth.

Stem cells could be harvested from hair follicles in parts of the body that have not lost their hair — particularly the back of the head, which is rarely affected by male pattern baldness — and implanted on bare areas of the scalp.

Even bald scalps are full of stem cells that renew the skin approximately every two weeks and they can help to regenerate hair. Last year Dr Fuchs’s team identified two key proteins that influence this process, which are promising targets for drugs that prompt stem cells to produce new follicles.

The team found that two distinct types of stem cell were both capable of forming healthy follicles.

“I think clinicians will be interested in the fact that both of these populations can produce hair follicles after culture,” Dr Fuchs said. “Previously researchers have done similar transplant experiments with dissected parts of the hair follicle. And while they have had evidence that hair-follicle structures were forming, they didn’t see generation of hair.

“In our experiments we saw quite a density of hair, in some cases at a density very similar to that of normal mouse fur. While we are not yet able to achieve such density a hundred percent of the time, the fact that we do get such density in some cases tells us that the system is working well. We just need to tweak it to the point where we can get such results consistently.”

The study also has implications for efforts to exploit skin stem cells for treating other diseases. If these cells turn out to be capable of growing into other types of tissue, such as pancreatic islet cells or nerve cells, it might be possible to use them in therapies for diabetes or Parkinson’s disease.

As skin stem cells are readily available in every adult, they would offer a more accessible and ethically acceptable alternative to embryonic stem cells, which are generally thought to hold the most promise for these potential treatments.

Embryonic stem cells are difficult and expensive to collect and raise ethical issues because they require the destruction of human embryos.

Landmark Research Details World First In Skin Repair Using Laboratory-Manufactured Human Skin